Non-spill bobbin case for sewing machines



Dec. 30, 1969 R. J. Ros 3,486,473

NON'SPILL BOBBIN CASE FOR SEWING MACHINES Filed Dec. 29, 1967 4Sheets-Sheet 1 CONTROL SYSTEM Fig. I.

Fig. l5. v

ZQ-wa 366 INVENTOR.

Roger J. Ross WITNESS I I '.v i I W7 ATTORNEY R. J. ROSS Dec. 30, 1969 NNON-SPILL BOBBIN CASE FOR S EWI NG MACHINES Filed Dec. 29. 1967 4Sheets-Sheet z m T m V m w/msss .BY w hz i AZTORNETY Dec. 30, 1969 R. J.Ross NON-SPILL BOBBINCASE FOR-'SEWING-MACHINES Filed Dec. 29, 1967 4Sheets-Sheet 5 S S o R J f e g 0 n ATTORNEY Dec. 30, 1969 R. J. ROSSNON'SPILL BOBBIN CASE FOR SEWING MACHINES Filed Dec. 29, 1967 4Sheets-Sheet 4 New INVENTOR.

. Roger J. Ross United States Patent 3,486,473 NON-SPILL BOBBIN CASE FORSEWING MACHINES Roger J. Ross, Herrick Drive, N.J., assignor to TheSinger Company, New York, N.Y., a corporation of New JerseyContinuation-impart of application Ser. No. 483,696, Aug. 30, 1965. Thisapplication Dec. 29, 1967, Ser.

Int. Cl. Db 57/26 US. Cl. 112-229 4 Claims ABSTRACT OF THE DISCLOSUREThis disclosure relates to a non-spill bobbin case for a loop taker of asewing machine in which a brake device is pivotally mounted in thebobbin case and normally biased into engagement with the bobbin toprevent bobbin rotation. Drawing the bobbin thread in a prescribedmanner will act to release the brake device from the bobbin to permitthe bobbin thread to be dispensed during the period of positive feed.Thereafter the brake is automatically re-applied to preventover-spilling of the bobbin thread.

Some of the operations which result in positive feed of the bobbinthread are the'setting of the lock stitch, the motion of a bobbin casesupport mechanism in aiding stitch formation, and drawing of the bobbinthread by a thread trimming mechanism for the trimming operation.

The brake device is associated with a tensioning means for the bobbinthread.

CROSS REFERENCE TO RELATED APPLICATION This application is acontinuation-in-part of my copending application, Ser. No. 483,696,filed Aug. 30, 1965 for Stitch Forming Mechanism for Sewing Machines.

BACKGROUND OF THE INVENTION Heretofore bobbin case frictional brakedevices relied on either the indirect application of a drag upon thebobbin or a continuous frictional force applied directly against thebobbin that resulted in both a variable tension of the bobbin thread andan inability to prevent spilling of the bobbin thread whenever it wasdrawn suddenly.

SUMMARY OF THE INVENTION In accordance with the present invention thenon-spill bobbin case provides stitch forming instrumentalities ofsewing machines with a brake device which normally prevents feeding ofat least one of the threads thereof, most usually the bobbin threadwhich is more susceptible of spilling, but is releasable responsive tothe positive drawing of said thread such as occurs when said thread isdrawn to form or set a stitch, or to be positioned for cutting thereof,or the like. The novel non-spill bobbin case may be used in almost anysewing machine, whether of conventional or particular design, or incombination with a trimming mechanism, or whenever the bobbin thread islikely to be subjected to intermittent drawing thereof.

It is therefore an object of the present invention to provide animproved non-spill bobbin case for a loop taker of a sewing machinewhich overcomes the prior art difliculties; which is usable incombination with a thread trimming mechanism; which is usable in anylock stitch sewing machine, conventional or otherwise; which permitspositive drawing of the bobbin thread; which uses a releasable brakedevice to prevent overspilling of the bobbin thread; which limits thedrawing of the bobbin thread during stitch formation to those periods ofpositive feed thereof; which uses a cooperative tensioning means and3,486,473 Patented Dec. 30, 1969 "ice BRIEF DESCRIPTION OF THE DRAWINGSThis invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a schematic representation of a sewing machine having atrimming device and controls therefor.

FIGURE 2 is a fragmentary perspective view of a loop taker, a needle andtake-up associated with a thread trimming mechanism shown in positionprior to operation thereof.

FIGURE 3 is a fragmentary perspective view showing the thread trimmingmechanism illustrated in FIGURE 2 shown immediately subsequent tooperation thereof.

FIGURE 4 is a perspective view of one form of the improved nonspillbobbin case.

FIGURE 5 is a partial sectional view of the closed end of the bobbincase of FIGURE 4 showing the brake device engaging the bobbin flange.

FIGURE 6 is a partial sectional view of the bobbin case of FIGURE 5showing the brake device released from the bobbin flange.

FIGURE 7 is a perspective view of another form of the improved non-spillbobbin case.

FIGURE 8 is a partial sectional view of the closed end of the bobbincase of FIGURE 7 showing brake device engaging the bobbin flange.

FIGURE 9 is a partial sectional view of the bobbin case of FIGURE 8showing the brake device released from the bobbin flange.

FIGURE 10 is a top plan view of still another form of the improvednon-spill bobbin case embodied in another type of a loop taker.

FIGURE 11 is a side elevational view taken along line 1111 of FIGURE 10.

FIGURE 12 is a top plan view of the bobbin case of FIGURE 10 includingthe needle and bobbin threads during manipulation of the needle threadloop by the loop taker.

FIGURE 13 is a top plan view of the bobbin case of FIGURE 10 with theneedle and bobbin threads in position for setting of a stitch.

FIGURE 14 is a side elevational view taken along line 14-14 of FIGURE13.

FIGURE 15 is a top plan view of the loop taker of FIGURE 10 and thesupporting arm therefor at one eX- tremity of oscillation of saidsupporting arm and illustrating in broken lines the path of motion ofthe loop seizing beak and the bobbin thread delivery guide means of thebobbin case.

DESCRIPTION OF THE INVENTION The novel non-spill bobbin case is designedfor use in a sewing machine, for example it may be embodied in aconventional sewing machine, such as is shown in FIG- URE 1 anddesignated generally as 20. In order to understand the presentinvention, a brief description of sewing machine 20 will be set forthherein, but for a more detailed description of this machine and theoperation components thereof reference may be had to the copendingUnited States patent application entitled Thread Trimming Mechanism forSewing Machines, United States Ser. No. 562,576, filed July 5, 1966.

The sewing machine 20 has a frame 22 that includes a bed 24 having astandard 26 thereon, from which is cantilevered a bracket arm 28 havingits opposite end terminate in a head 30 that overhangs the bed 24. Thestitch forming instrumentalities, generally designated as 32, aremounted in the frame 22 of the machine 20 as will be more fullyexplained hereinafter. A trimming mechanism 34 is disposed in the bed 24adjacent a loop taker 36 of the stitch forming instrumentalities 32. Theframe 22 is suitably supported in the top of a leg supported table 37.

A suitable control system 38 is adapted to operate the trimmingmechanism 34 and includes the schematically represented units shown inFIGURE 1. A needle positioning device including a clutch-and-timer unit40 is secured in place of the conventional balance wheel and will act totime the operation of the trimming mechanism 34. A detailed descriptionof unit 40 may be had by reference to United States Patent No.2,942,564. The clutch of the unit 40 is double acting and is biased toconnect a transmitter belt 42 driven by a conventional clutch-braketransmitter 44 to the arm shaft (not shown) of the sewing machine 20. Onsignal from the control system 38 the clutch-and-timer unit 40 drivesthe clutch therein into a position connecting an auxiliary belt 46 tothe arm shaft. The auxiliary motor 48 is operable at a lower speed whichpermits slow and accurate needle positioning. A normallyclosed controlswitch 50 is secured to the operating lever 52 of the transmitter 44.The lever 52 operates to control the clutch and brake thereof. Thecontrol switch 50 will be opened to remove the power from the units ofthe control system 38 when the operating lever 52 is lowered bydepressing a treadle 54. Lowering of the lever 52 releases the brake andengages the clutch of the transmitter 44 to drive the belt 42.

When the operator raises the lower length of the pitman 56 connectingthe treadle 54 to the lever 52 a normally-open switch 58 will be closedto cause the control system 38 to position a needle 60 of the stitchforming instrumentalities 32 to extend downwardly into the bed 24. Thenthe transmitter 44 will be in a braked condition and the system will beprepared for trimming. A switch 62 at the treadle is provided to permitsewing of additional stitches, and thereafter, the operator actuates theswitch 58 to place the needle 60 in the down position and prepare thesystem for the trimming operation.

The stitch forming instrumentalities 32, illustrated in FIGURES 2 and 3,includes the vertically reciprocated needle 60 and associated threadtake-up member 62 which manipulates the needle thread in theconventional manner, and cooperates with the loop taker 36 toconcatenate the needle and bobbin threads 64 and 66, respectively, intoa series of lock stitches, shown schematically and designated generallyas 68. The loop taker 36 includes a rotary hook which is secured to abed shaft 72 journaled in the bed 24 to rotate the hook 70 tworevolutions for each vertical reciprocation of the needle 60 as isconventional for this type of sewing machine 20. Journaled within therotary hook 70 is a bobbin case 74 which is prevented from rotating by arotation restraining finger 76 secured to the bed 24 of the sewingmachine 20 and inserted into a rotation restraining notch 78 in thebobbin case 74. The rotary hook 70 includes a hook beak 71 whichpartakes of two revoltuions in cooperation with each verticalreciprocation of the needle 16 to seize loops of thread from the needleand to concatenate the seized thread loops about the bobbin case to formlock stitches. A bobbin 80 carries a supply of the bobbin thread 66therein and is disposed in the bobbin case 74 so that the axis ofrotation of the bobbin 80 is coincident with the axis of rotation of thebed shaft 72.

Subsequent to actuation of the switch 58 to place the needle 60 in thedown position, the operator shifts a knee pedal 81 to close a switch 83,shown in FIGURE 1 which sets the trimming mechanism 34 into operation.The trimming mechanism 34 includes a thread engaging element or finger82 and a blade 84 suitably connected to be actuated by the controlsystem 38. The closing of the switch 83 causes the thread engagingfinger 82 to be driven into the position represented in FIGURE 2,simultaneously raising the needle 60 to the up position and on raisingof the needle the finger 82 draws the needle and bobbin thread 64 and66, respectively, prior to the control system 38 effecting operation ofthe blade 84 to cut the same, as is illustrated in FIGURE 3.

The thread engaging finger 82 has a thread catching hook 86 on the endthereof adjacent the bobbin case 74, which hook is insertable into athread catching aperture 88 formed in the otherwise conventional bobbincase 74. The thread catching hook 86, as shown in FIGURE 2, will bepositioned in the thread catching aperture 88 so that the bobbin thread66 and the loop formed on the needle thread 64 will be pulled against itby the counter-clockwise rotation of the hook beak 71 whereby onretraction of the thread catching finger 82, the thread catching hook 86will draw the bobbin thread 66 andthe loop formed of the needle thread64 away from the rotary hook 70 and to the left, as .viewed in FIGURE 3.However, the work limb N of the needle thread 64 and the bobbin thread66 passing to the work represented by the line of stitches 68 are drawnbehind the rotation restraining finger 76, whereas the needle limb N ofthe needle thread 64 is drawn by the hook beak 71 into a positionfinally overlaying the rotation restraining finger 76, as shown inFIGURE 3.

The thread catching hook 86 is preferably inserted into the threadcatching aperture 88 when the needle 60 is in its lower dead centerposition, approximately at the time when the hook beak 71 is firstengaging a loop of the needle thread 64. As the hook beak 71 rotates theneedle loop is pulled thereby against the thread catching finger 82, andthe bobbin thread 66 is positioned in a slot 92 in the bobbin case 74which slot 92 is aligned with the thread catching aperture 88 and thepath traversed by the thread catching finger 82 and the hook 86 during astroke thereof.

After the thread limbs have been caught and drawn outwardly by thethread catching hook 86 to a sufficient length to permit cutting of theneedle and bobbin threads 64 and 66 respectively, for resumption ofsewing following trimming without manipulation, the blade 84 can bedrawn across the work limb N of the needle thread 64 and the bobbinthread 66. Because the blade 84 travels below the needle limb N thatlimb will not be trimmed and will remain long enough for commencement ofthe next sewing operation. When the cutting stroke occurs, preferably attop dead center of the needle 60, the needle take-up member 62 will beraised, in the conventional manner, for tightening the last stitch 68and providing tension on the threads. Provisions of adequate tensionpermits the use of a single blade 84 operative without an opposingblade, i.e., without a scissors action, to trim the limbs of thread thesame as if they were struck by a blade with considerable impact. Tensionalso assures that the needle limb N will not be cut because it isretained by the thread catching hook 86, the rotation restraining finger76 and the wall of a needle aperture 94 in a throat plate, (not shown)sufficiently distant from the blade 84.

The trimming mechanism 34 described herein is basically the same as thatshown and described in the United States patent application for a ThreadTrimming Mechanism for Sewing Machines, United States Ser. No. 562,576,filed July 5, 1966, to which reference may be had for a more completeunderstanding thereof.

In any event, the present invention is contemplated for use with any oneof a variety of trimming mechanisms or for that matter may be associatedwith any sewing machine or device thereof the operation of which resultsin the bobbin thread being drawn intermittently, suddenly or other thanat a constant rate so as to produce a tendency for spilling of thebobbin thread that would interfere with the normal feeding thereof. Itis the principal object of the present invention to prevent the spillingof the bobbin thread by providing a non-spill bobbin case as isillustrated in the several embodiments of the present invention setforth hereinafter.

In the embodiment of the invention illustrated in FIG- URES 4, 5 and 6an improved non-spill bobbin case 100 is shown adapted for use in asuitable loop taker (not shown) of a lock stitch sewing machine, forexample the. loop taker 36 of sewing machine which machine may include atrimming mechanism 102 generally represented in FIGURE 4 by the hookended thread engaging finger.

The bobbin case 100 has an end wall 104 in which is diametricallydisposed a pivotable grip 106 on one side of which is formed a rotationrestraining notch 108. An annular flange 110 extends from the outerperiphery of the endwall 104 perpendicularly therefrom so that the case100 is substantially basket shaped.

The end of the case 100' opposite the wall 104 is open to receive abobbin 112. The bobbin has an annular hub 114 having an inner circularflange 116 and an outer circular flange 118 connected at either endthereof. A supply of bobbin thread 120 is wound about the hub 114between the flanges 116 and 118. The bobbin 112 is free to rotaterelative a bobbin case 100, with the axis of rotation substantiallyparallel to the flange 110.

On the side of the case 100 opposite the notch 108 an elongated slot 122is formed for a brake device that is designated generally as 124. Thebrake device 124 includes a lever 126 having a brake finger 128extending from one end thereof and a slotted thread engaging portion orfinger 130 formed at the other end thereof. The lever 126 is pivotallyconnected into the slot 122 by a pin 132 so as to extend substantiallyparallel to the end wall 104, with fingers 128 and 130 substantiallyperpendicular thereto. The fingers 128 and 130 and the pin 132 aredisposed parallel to the axis of rotation of the bobbin 112.

A tensioning means in the form of a biasing spring 134 is connected tothe flange 110 by a screw 136 which is turnable to adjust the biasingforce exerted thereby. An end 138 of the spring 134 engages the brakefinger 128 to bias it into engagement with the flange 118 of the bobbin112. The other end 140 of the spring 134 extends along the flange 110passing under the thread engaging finger 130 to define a thread guidingmeans.

The flange 110' of the bobbin case 100 has thread guiding means formedon either side of the spring thread guiding means 140. Moreparticularly, a slot 142 is formed adjacent the finger 130, while athread guide 144 is formed beyond the guiding means 140 on the outerperiphery of said flange. The bobbin thread will be passed out of thecase 100 through the slot 142 of the flange 110 to be disposed throughthe slotted thread engaging finger 130 prior to passing under theguiding means 140 which presses the thread against the flange 100,before the thread finally exits out of the hole in the thread guide 144from which point it may be drawn intermittently by the stitch forminginstrumentalities (not shown) or other mechanism, or the like.

The brake finger 128 of the brake device 124 is normally biased intoengagement with the flange 118 of the bobbin 112 and thereby acts toprevent issuance of the bobbin thread 120. However, the brake finger 128will be released whenever the bobbin thread 120 is drawn to create anopposing force at the thread engaging finger 130 which overcomes thebiasing force of the spring 134 and results in the lever 126 pivoting asillustrated in FIGURE 6, to release the brake finger 128 from engagementwith the flange 118. So long as the bobbin thread 120 is beingpositively fed the thread engaging finger 130 will continue to be urgedin the direction of the flange 110 thereby permitting the bobbin 112 torotate 6 and the bobbin thread to be fed. On the cessation of bobbinthread feeding the tension spring 134 will immediately bias the brakefinger 128 into re-engagement with the flange 118 to brake the bobbinturning and prevent over-spilling of the bobbin thread 120.

The distance from the pivot pin 132 to the thread engaging finger issubstantially three times longer than the distance from the pivot pin132 to the brake finger 128 whereby the force exerted at the finger 130need be only a fraction of that exerted on the brake finger 128 toovercome the same. In other words the moment arm from the pin 132 to thefinger 130 being three times greater will require a force of slightlymore than onethird that of the spring 134 force.

Accordingly, the release of the brake finger 128 is effected almostimmediately on the bobbin thread 120 being drawn. In this manner, thereis no interference with the normal sewing operation or other acts whichresult in a drawing of the bobbin thread 120. Additional benefitsderived from the use of the brake device 124 are that of having thebobbin thread 120 remain under constant tension in that there is nochange in the effective moment arm, regardless of whether the bobbinthread supply is full or empty because said moment arm will not bemeasured from within the case 100, but will take effect from the pointthe thread crosses over the finger 130 in a manner that was not possiblein the bobbin cases of the prior art.

In the embodiment of the invention illustrated in FIG- URES 7, 8 and 9an improved non-spill bobbin case 200 is shown adapted for use in asuitable loop taker (not shown) of a lock stitch sewing machine, forexample, the loop taker 36 of sewing machine 20, which may include atrimming mechanism 202 generally represented in FIG- URE 7 by the hookedended thread engaging finger.

The bobbin case 200 has an endwall 204 in which is diametricallydisposed a pivotable grip 206 on either side of which is formed arotation restraining aperture or notch 208. An annular flange 210extends from the outer periphery of the endwall 204 perpendicularlytherefrom so that the case 200 defines a substantial basket shape.

The end of the case 200 opposite the wall 204 is open to receive abobbin 212 therein. The bobbin 212 has an annular hub 214 having aninner circular flange 216 and an outer circular flange 218 connected ateither end thereof. A supply of bobbin thread 220 is wound about the hub214 between the flanges 216 and 218. The bobbin 212 is free to rotaterelative a bobbin case 200, with the axis of rotation substantiallyparallel to the flange 210.

On the side of the case 200, adjacent the pivot connection of the grip206, a brake device designated generally 224 is pivotally disposed inthe flange 210 of the case 200.

The brake device 224 includes a lever 226 having a combined brake andthread engaging portion or finger 230 formed at one end thereof toextend across the flanges 216 and 218. The lever 226 is pivotallyconnected into the flange 210 by an integral pin 232 formed at the otherend thereof, with the finger 230 and the pin disposed substantiallyperpendicular to the end wall 204. The finger 230 and the pin 232 aredisposed parallel to the axis of rotation of the bobbin 212.

A tensioning means in the form of a biasing spring 234 is anchored tothe flange 210 by a screw 236a, with a second screw 236k turnable in theflange 210 to adjust the biasing force exerted by the spring 234. A freeend 238 of the spring 234 engages the lever 226 to bias the brake finger230 into engagement with the bobbin flanges 216 and 218. Intermediatescrew 23Gb and end 238 the spring 234 has a thread tension portion 240under which the bobbin thread passes to be guided and yieldably pressedagainst the flange 210. The flange 210 has a built-up section 242 whichcarries the brake device 224 and tensioning spring 234. A recess 244extends on the bobbin side of the periphery of the section 242. Therecess 244 has a radial thread exit slot 246 at one end and an enlargedslotted aperture 248 at the other end thereof, each disposed tocommunicate with the open end of the case 200. Another radial slot 250is formed adjacent the aperture 248 and spaced therefrom.

The bobbin thread 220 follows a serpentine path through the slots;issuing out of the slot 250 to come into contact with the thread tensionportion 240 of the spring 234, passing into the aperture 248 and aboutand under the lever 226 to come into contact with the thread engagingfinger 230, and finally issuing from the slot 246 from which point itmay be drawn as need be. The free end 238 of the spring 234 is bent intothe aperture 248 to engage the lever 226 and urge the finger 230 intoengagement with the flanges 216 and 218.

Accordingly, the finger 230 of the brake device 224 is normally biasedinto engagement with the flanges 216 and 218 of the bobbin 212 andthereby acts to prevent issuance of the bobbin thread 220. However, thefinger 230 will be released whenever the bobbin thread 220 is drawn tocreate a lifting force at said finger 230 which overcomes the biasingforce of the spring 234 and results in the lever 226 pivoting asillustrated in FIGURE 9, to release the finger 230 from engagement withthe flanges 216 and 218. So long as the bobbin thread 220 is posi tivelyfed or drawn the finger 230 will remain out of engagement with theflanges 216 and 218 thereby permitting the bobbin 212 to rotate and thebobbin thread 220 so as to be fed. On the cessation of the bobbin threadfeeding the tension spring 234 will immediately bias the finger 230 intore-engagement with the flanges 216 and 218 to brake the bobbin turningand prevent over-spilling of the bobbin thread 220.

Once again the force required to effect release of the finger 230 of thebrake device 224 is sufliciently small so as not to interfere with thedrawing of the bobbin thread 220 during normal sewing operations or thelike. Though the finger 230 serves the dual function of both braking andthread engaging, it will nevertheless permit the bobbin thread to remainunder substantially constant tension regardless of whether the supply ofbobbin thread is full or empty.

In certain applications it may be desirable to pivot the brake deviceabout an axis perpendicular or at an inclined angle to the axis ofrotation of the bobbin. The improved non-spill bobbin case depictedhereinafter sets forth a perpendicular arrangement. This and other minormodifications, such as the presence or absence of thread slots upon thecase, are intended to be within the scope of the present invention.

In the embodiment of the invention illustrated in FIG- URES 10 throughthe novel non-spill bobbin case is designated generally as 300 and is acomponent of a loop taker 302 having a loop seizing beak 304 whichprescribes a curtate epicycloidal path as illustrated by the dashed line306 in FIGURE 15.

The loop taker 302 will be embodied in a sewing machine (not shown) inwhich the loop taker 302 and a needle 308 form part of the stitchforming instrumentalities of said machine. A more detailed descriptionof the sewing machine and the stitch forming instrumentalities thereofin whch the loop taker 302 is embodied may be had by reference to theUnited States patent application to which the present case is acontinuation-in-part, namely, the pending application for a StitchForming Mechanism For Sewing Machines, United States Ser. No. 483,- 696,filed Aug. 30, 1965. Only those components and the operation thereofwhich need be described so as to provide a complete understanding of thepresent invention are set forth herein.

The sewing machine (not shown) has a bed plate 310, shown in FIGURE 11,with an aperture 312 therein covered by a throat plate 314 which isformed with a needle aperture 316 and a plurality of slots (not shown)for use by a suitable work feeding mechanism (not shown) of any knownvariety.

The loop taker 302 of this form of the invention is a shuttle 318journaled for turning movement in an upwardly open counterbore 320formed in an oscillating arm 322 fulcrumed on a shoulder screw 324threaded to the underside of the bed plate 310. A shuttle driver 326 iscarried within the counterbore 320 beneath the shuttle and is connectedto the top of a shaft 328 journaled in a bore 330 concentric with thecounterbore 320 and through the oscillating arm 322. Beneath theoscillating arm 322 a pinion 332 is secured by a set screw 334 to theshuttle driver 328 as illustrated in FIG. 11.

Carried beneath the oscillating arm 322 is a plate 336 formed with anarcuate gear segment 338 arranged to mesh with the pinion 332. Duringsewing the plate 336 remains stationary relative to the sewing machineframe being secured in position by the fulcrum screw 324 for oscillatorylever 322 and also by an adjustable clamp screw (not shown) threaded tothe underside of the bed plate 310 so as to eflect adjustment of theturning of the shuttle relative to the reciprocation of the needle, foroptimum loop taking effectiveness.

The shuttle 318 includes the improved bobbin case or basket 300 having abottom wall 340 with a central stud 342 therein and bounded by upwardlyextending walls that terminate adjacent the open top thereof. Formedabout slightly more than half of the periphery of the case 300 is anarcuate bearing rib 344 which is journaled snugly in the counterbore 320of the supporting arm 322 and which is formed at one extremity of theloop seizing beak 304.

As illustrated in FIGURES 10, 12 and 13 the cylindrical case 300 isoffset slightly relative to the center of curvature of the annularbearing rib 344 so that the cylindrical case 300 will similarly beslightly eccentric to the axis of the shaft 328. The counterbore 320extends to the free extremity of the supporting arm 322 providing anopening 346 in the passage through which the loop seizing beak 304 mayseize a needle thread loop. A gib 348 is secured by screws 350 over thesupporting arm overlies the shuttle bearing rib 344 to constrain theshuttle therein.

The shuttle driver 326 is formed with an arcuate rib 352 which extendsbetween the extremities of the shuttle bearing rib 344 thus to impartoscillatory motion to the shuttle about its central aXis as the pinion332 is turned in mesh with the gear 338. The shuttle, in addition, iscarried bodily by the supporting arm 322 for oscillatory motion aboutthe supporting arm fulcrum 324. The resulting motion of any point on theshuttle is epicycloidal. In particular, the path of motion of the loopseizing beak 304 of the shuttle, since it is disposed at a larger radiusthan the pinion 332 will partake of a curtate epicycloidal path asillustrated by the dashed line 306 in FIGURE 15. An advantage of theepicycloidal motion resides in the ease and speed with which needlethread loops are seized, manipulated completely about the shuttle, andshed from the shuttle. Indicated at 354 in FIGURE 15 is the loop seizingpoint along the path of motion of the loop seizing beak, and indicatedat 356 is the point along the path of motion of the beak at which theneedle thread loop will have been carried completely about the shuttle.Beyond the point 356, the shuttle beak will no longer influence theneedle thread loop and the take-up (not shown) will assume its role ofdrawing up the thread. FIGURES 10 and 11 illustrate the shuttle with thebeak position substantially at the needle thread loops seizurecorresponding to the point 354 in FIGURE 15. FIGURE 12 illustrates theshuttle with the beak 304 positioned substantially at the needle threadshedding point 356 as illustrated in FIGURE 15. FIGURE 14 illustratesthe shuttle at the extreme position of motion with the beakcorresponding to a point 356 in FIGURE 15.

FIGURES 11 and 14 best illustrates the bobbin 360 and the provision forcontrolling the bobbin thread tension. The bobbin 360 comprises a bottomflange 362 and a central hub 364 formed with a blind bore 366accommodating a stud 342 within the shuttle case or basket 300. A topflange 368 of the bobbin is formed with an annular recess 370 of whichthe inner diameter is undercut as at 372 to provide a fingernail gripfor removing and replacing the bobbin in the basket.

For accommodating the bobbin thread, the shuttle basket 300 is formedwith a thread slot 374 leading from the upper edge of the basket to athread eyelet 376 near the bottom wall 340 of the shuttle.

Above the eyelet 376 the shuttle basket is formed with a recess 378 fromwhich a thread guiding groove 380 extends to the upper edge of thebasket 300. Pivoted on a pin 382 on the side of the bobbin case orshuttle basket 300 is a bobbin brake device 384 of which a lower arm 386depends into a slot in the shuttle base in position contiguous to therim of the bottom flange 362 of the bobbin. An upper arm 388 of thebrake lever or device 384 underlies the thread guiding groove 380 and isfurther provided with a lateral finger 390 across which the bobbinthread is directed between the eyelet 376 to the thread guiding groove380. Secured by a screw 392 to the exterior of the shuttle basket 300 isa leaf spring of which an upper arm 394 extends across the upper arm 388of the brake device and across the thread slot 374, and a lower arm 396extends opposite the lower arm 386 of the brake device. The action ofthe spring arm 396 biases the brake arm 386 against the bottom bobbinflange to deter overspinning of the bobbin. In addition, the bobbinthread in passing between the upper arm 388 and the spring arm 396 willbe subjected to a tensioning friction. When, however, the bobbin threadis drawn taut diametrically across the bobbin from the thread guidinggroove 380 as in the extreme position of the shuttle as illustrated inFIGURE 13, the bobbin thread will apply a counterclockwise turningmovement to the brake device 384 as viewed in FIGURE 14 and release boththe bobbin thread tension and braking influence on the bobbin.

Such bobbin thread tension release occurs automatically after eachstitch has been set and provides a limit on the stitch setting tensionapplied to the bobbin thread. When the bobbin thread tension is thusreleased, an increment of bobbin thread equal to that used forming thepreceding stitch may be withdrawn from the bobbin free of influence ofthe bobbin thread tensioning means, and moreover without adverselyinfluencing the preceding said stitch.

In the dot and dashed line in FIGURE 15 designated generally as 398 isindicated the path of motion of the thread guiding groove 380 on theshuttle basket 300. Due to the eccentricity of the shuttle basket thepath 398 takes the form of a modified curtate epicycloid. It will beapparent from the path of motion 398 illustrated in FIG- URE 15 that aconsiderable degree of control is exercised over the position of theslack bobbin thread while the shuttle occupies positions other than thestitch setting position of the FIGURE 13, i.e., since the thread guidinggroove 380 partakes of a curtate epicycloidal loop denoted at 400 inFIGURE 15, the slack bobbin thread will be partly taken up during stitchformation, and moreover, said slack bobbin thread by virtue of thisadvantageous motion will be urged away from the path of the needle.

Accordingly, the novel non-spill bobbin case of the present inventionmay be embodied in any loop taker, regardless of type, such as a shuttleor rotary hook, or the like.

It will be understood that various changes in the details, materials,arrangements of parts and operating conditions which have been describedherein and illustrated in order to explain the nature of the inventionmay be made 10 by those skilled in the art within the principles andscope of the invention.

Having thus set forth the nature of the invention, what I claim hereinis:

1. A non-spill bobbin case for a loop taker of a sewing machinecomprising:

(a) a thread carrying bobbin having a hub and at least one circularflange disposed in the bobbin case,

(b) a brake device is pivotally connected to the bobbin case to pivotabout an axis parallel to the axis of rotation of the bobbin,

(c) the bobbin case includes an annular flange having slot meanstherein,

(d) tensioning means carried on the bobbin case to bias the brake deviceinto engagement with the flange of the bobbin and to place the threadunder tension,

(e) the brake device includes a thread engaging portion thereof,

(f) the tensioning means includes guide means cooperating with the slotmeans and the brake device to permit the thread of the bobbin to exitfrom the bobbin case and passes about the thread engaging portion of thebrake device, and

(g) the thread engaging portion of the brake device on drawing of thethread of the bobbin adapted to cause the brake device to pivot out ofengagement with the flange of the bobbin whereby said thread may bedrawn to form or set a stitch or prior to cutting thereof.

2. The combination claimed in claim 1 wherein:

(a) the brake device includes a lever pivotally connected intermediatethe ends thereof to the flange of the bobbin case,

(b) a brake finger is formed at one end of the lever normally to bebiased into engagement with the flange of the bobbin,

(c) a thread engaging finger defined by the thread engaging portion isformed at the other end of the lever and on drawing of the threadengaged therewith is adapted to pivot the lever to release the brakefinger from contact with the flange of the bobbin.

3. The combination claimed in claim 2 wherein:

(a) the brake finger and the thread engaging finger are disposedparallel to the axis of rotation of the bobbin.

4. The combination claimed in claim 1 wherein:

(a) the brake device includes a lever pivotally mounted to the flange ofthe case at one end thereof,

(b) a finger formed at the end of the lever remote from the pivotableconnection thereof,

(c) the finger normally biased into engagement with the flange of thebobbin, and has the thread of the bobbin in contact therewith on theopposite side thereof from the biasing force of the tensioning meanswhereby on pulling of the thread the force of the tensioning means isovercome to release the finger from engagement with the flange of thebobbin to permit a supply of bobbin thread to be drawn from the bobbincase.

References Cited UNITED STATES PATENTS 347,804 8/1886 Hubbard 242-128 388,323 8/ 1888 Vannett 112-231 1,234,398 7/1917 Schwarzmann 112-981,792,238 2/1931 Parkes 112-231 1,995,278 3/ 1935 Kessler 112-2282,555,658 6/1951 Ritter 112229 2,975,738 3/ 1961 Hoppe 112-229 XR3,038,429 6/ 1962' Ketterer et al. 112-252 XR JAMES R. BOLER, PrimaryExaminer

